Report

Horizontal crank position affects economy and upper limb kinematics of recumbent hand cyclists.

Horizontal crank positions of 97% and 100% are more economical and positively affect upper-limb kinematics in hand cyclists.

Lead academic:
Benjamin Stone
Additional academics:
Barry Mason, Martin Warner, Vicky Goosey-Tolfrey
Funder:
Engineering and Physical Sciences Research Council. Supported by the English Institute of Sport, British Cycling and the Peter Harrison Centre.

Introduction:

Recumbent handcycling is a recreational and sporting exercise modality for individuals with lower limb impairments. The interaction between the athlete and the hand-bike is critical for handcycling performance. Manipulating the configuration of the interface between the athlete and the hand-bike has been found to effect mechanical efficiency, economy, and sprint power in handcycling.

The horizontal crank position has been identified, through a series of interviews of participants with expert views and/or experience of recumbent handcycling, as having a substantial impact on power production, handcycling efficiency, and endurance performance. However, previous studies manipulated horizontal crank position by measuring elbow extension angle statically with a goniometer, which can be inaccurate and unreliable.

Study aim: To determine the effects of horizontal crank position, relative to arm length, on handcycling economy and upper limb kinematics (thorax, clavicle, scapula, humerus, forearm, hand) in trained hand-cyclists.

Methods:

Fifteen trained hand-cyclists performed trials at 50% and 70% of their peak aerobic power output (POPeak), determined during a maximal exercise test, in each horizontal crank position.

Four horizontal crank positions, 94%, 97%, 100%, and 103% of arm length, were investigated. Horizontal crank positions were defined as the distance between the acromion angle to the centre of the handgrip, while the crank arm was parallel to the floor and pointing away from the participant.

Economy and upper limb kinematics were calculated during the final minute of each 3-min trial.

Main findings:

  • Handcycling economy was significantly affected by horizontal crank position at 70% POPeak but not at 50% POPeak.
  • At 70% POPeak, the 97% horizontal crank position was more economical than 94%, and the 103% positions.
  • At 50% POPeak, although not significant, the 97% and 100% horizontal crank positions were more economical than the 94%.
  • Horizontal crank position significantly affected upper limb kinematics (clavicle, scapular, shoulder, elbow, and wrist).
  • Horizontal crank position had no significant effects on thorax kinematics.
  • 97% and 100% horizontal crank positions were more economical than 94% and 103% positions at 70% POPeak.
  • Positioning the cranks too far (103%) from the shoulders caused an increase in clavicle protraction, scapular internal rotation, shoulder flexion, shoulder adduction, and elbow extension.
  • Conversely, positioning the cranks too close (94%) from the shoulders caused a reduction in scapular internal rotation, elbow flexion, and shoulder extension.
  • Horizontal crank position has a significant effect on handcycling economy and upper limb kinematics.

Reference:

Stone B, Mason BS, Warner MB, Goosey-Tolfrey VL. Horizontal Crank Position Affects Economy and Upper Limb Kinematics of Recumbent Handcyclists. Med Sci Sports Exerc. 2019 Nov;51(11):2265-2273. DOI:  PMID: 31634293.